DESCRIPTION: In the summary statement the principal investigator was criticized: (1) for the lack of a central hypothesis linking together the three specific aims; (2) the absence of any obvious decision tree guiding the proposed studies; and (3) the lack of preliminary data documenting the feasibility of conducting a number of the proposed studies. In response to these specific criticisms the application has been considerably revised and as a result has been improved. Among these revisions is the elimination of all studies with antibodies against the muscarinic receptors m1, m3, m4 and m5 and all EM work on post-mortem human specimens. In addition, the specific hypotheses and decision trees guiding the proposed experiments are more elaborately presented. To this end the principal investigator prepared an overview figure summarizing both the known components of the cholinergic pathways in the primate cerebral cortex and those unknown components that will be addressed by the present proposal.